The isolation of glycosidases that can selectively attack glycoproteins of influenza and Rous sarcoma viruses will be attempted. The effect of such glycosidases on the structure and function of the two enveloped animal viruses will be studied. A comparison will be made of the DNAs produced in vitro by transcription of Rous sarcoma virus RNA in the endogenous system versus purified system. Possibilities of genetic mapping and of transfection using the Rous virus DNA will be investigated. Bibliographic references: Protein Synthesis in Tobacco Protoplasts Infected with Tobacco Mosaic Virus. R. Paterson and C. Arthur Knight. Virology 64, #1, 10-22, 1975 (March).